Examination of fecal pellet physical characteristics of an invasive drywood termite, Cryptotermes dudleyi (Isoptera: Kalotermitidae): A potential approach for species marker and non-destructive monitoring method

Abstract

Cryptotermes, one of the major drywood termite genera in Indonesia, is a cryptic species that isolates their presence inside a wood piece. Due to its cryptic lifecycle hidden away inside wood, monitoring its presence and also identifying the corresponding species has been a difficult process. One of the Cryptotermes species, native to Java island, Indonesia, is Cryptotermes dudleyi. In this preliminary study, we used C. dudleyi as a species model to find out whether fecal pellet physical characteristics can be used as a stable species marker to assist in non-destructive monitoring surveillance. The characteristics used were maximum diameter, diagonal width of maximum diameter, and 2D surface area and area perimeter. The study used fecal pellets from orphaned and mature colonies and three different dietaries (grass, hardwood, and softwood) to check whether the characteristic value of fecal pellets is narrow over various influences. The results showed that each characteristic tends to have unique mean and also its unique value range which depends on their collection site condition. Due to unique means and value range, the species marker become not so accurate and not robust enough as consequences in accommodating these unique means and value range. On the other hand, employing completely new clustering based on like-like axiom on individual fecal pellets may results in robust species marker as long as adequate data comparison from other species fecal pellets to validate the species marker is available.